Basic copper carbonate (BCC) is a well-known chemical compound which has a variety of uses including, without limitation, as a pigment, insecticide and algaecide. BCC may be represented by the formula (CuCO3)x(Cu(OH)2)y, and may occur as malachite (Cu2CO3(OH)2, wherein x and y are 1) or azurite (Cu3(CO3)2(OH)2, wherein x is 2 and y is 1).
Azurite and malachite differ in color, as well as in copper and carbon dioxide content. Azurite, deep blue in color, contains about 55.5% copper and about 25.5% CO2. Malachite, in contrast, is bright green in color, and contains about 57.5% Cu and about 19.9% CO2.
Various methods for the preparation of BCC are known in the art. One traditional method of making BCC may be referred to as “caustic boil.” In this method, copper metal is dissolved in an ammonia/ammonium carbonate solution, via well-known techniques developed in the 1800s, followed by boiling off the ammonia to precipitate BCC. The caustic boil method is an energy intensive process and therefore less desirable. Another method contemplates adding sodium carbonate to a solution of copper sulfate, followed by filtering, washing and drying. This method results in BCC contaminated with sodium and sulfate and is therefore less desirable.
A method for preparing BCC which provides advantages over known methods would be desirable.